Wednesday, December 12, 2007

Humans still evolving?

This pretty shameless story was covered by a number of leading UK broadsheets yesterday. So called 'journalists' at each of these publications had clearly all received the same press-release (or wire feed) and none apparently felt the need to question the agenda behind this research from the University of Wisconsin. You don't have to be a genius to figure it out though:

If human evolution is speeding up thanks to "the tendency to start families later in life" then you would have to presume that people in the small number of well-off nations where this is generally the case will somehow become more evolved than all those darkies in Africa.

Which should of course come as a surprise to anyone that knows the first thing about human evolution because a) Africa is and has always been the main factory of human evolution b) it has the most genetically-diverse human populations on Earth and c) there needs to be some fundamental agent of selection for evolution to work at all. Where in the world are you most likely to die before getting the chance to pass on your genes? Not in countries where women have children through artificial insemination at the age of 45 methinks.

"The study also suggests that human races in different parts of the world are becoming more genetically distinct", Ian Sample, scientific correspondent of the Guardian reports. Now this is a tricky one, because the consensus, like it or not, is that race is "biologically meaningless". (You'd have thought Sample might have mentioned this.)

To quote Wikipedia: "The 0.1% genetic difference that differentiates any two random humans is still the subject of much debate. The discovery that only 8% of this difference separates the major races led some scientists to proclaim that race is biologically meaningless. They argue that since genetic distance increases in a continuous manner any threshold or definitions would be arbitrary. Any two neighboring villages or towns will show some genetic differentiation from each other and thus could be defined as a race. Thus any attempt to classify races would be imposing an artificial discontinuity on what is otherwise a naturally occurring continuous phenomenon."

So at the very least the scientists at Wisconsin are 'bravely' trying to re-open this issue.

Having said all this, one thing I would add is that I have often paused on the platform of Leicester Square tube station to consider the near perfect colour match between the little mice that scurry around the tracks and the grimy concrete of their environment. What might the selection pressure be? Surely they don't have a substantial predator population down there?